Using R to change raster projection

I'm trying to change raster projection using R and the raster package. The input raster projection is Lambert Azimuthal; the parameters are here:

Coordinate System:
Lambert_Azimuthal_Equal_Area
False_Easting: 4321000,000000
False_Northing: 3210000,000000
Central_Meridian: 10,000000
Latitude_Of_Origin: 52,000000
GCS_ETRS_1989
Datum: D_ETRS_1989
Prime Meridian: 0


PROJCS
 ["ETRS_1989_LAEA",
   GEOGCS ["GCS_ETRS_1989",
           DATUM ["D_ETRS_1989",
                  SPHEROID ["GRS_1980",6378137.0,298.257222101]],
           PRIMEM["Greenwich",0.0],
          UNIT["Degree",0.0174532925199433]],
   PROJECTION["Lambert_Azimuthal_Equal_Area"],
   PARAMETER["False_Easting",4321000.0],
   PARAMETER["False_Northing",3210000.0],
   PARAMETER["Central_Meridian",10.0],
   PARAMETER["Latitude_Of_Origin",52.0],
   UNIT["Meter",1.0]]

I need to convert them to simple rasters in ESRI ASCII format, using longitude and latitude coordinates, with a Mercator-style projection, with a cell size of 0.1 degrees (I hope I explain myself well enough, because I don't have enough GIS skills, sorry). What I need are rasters in format .ASC where each value of the raster corresponds to a single cell of size N x N, where N is in degrees (e.g. 0.1 degrees), and the raster coordinates are in longitude/latitude.

I tried to use raster library in R, and follow examples found for the projectRaster function. But after many attempts using many several parameters, I wasn't be able to make it correctly. I think I'm not using the correct parameters for projection, datum, or something like this.

Here's what I tried. I load the raster in R, then I set its projection using:

>crs(r)<-"+proj=laea +lat_1=52 +lon_0=-10 +ellps=GRS80"

Then I define the output projection and I try the conversion and save:

>newproj <- "+proj=lonlat +lat_1=52 +lon_0=-10 +ellps=WGS84"
>pr2 <- projectRaster(r, crs=newproj, res=0.1)
>writeRaster(pr2, "newraster.asc", overwrite=TRUE)

No error messages, but resulting raster is not correctly projected (country borders don’t match, countries are slightly distorted).

Thanks for any help!

Solution

Given the description of the projection you provide, this seems wrong:

crs(r) <- "+proj=laea +lat_1=52 +lon_0=-10 +ellps=GRS80"

As you do not include the false northing and easting parameters; and lat_1 should probably be lat_0. This may be better:

crs(r) <- "+proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000 +ellps=GRS80 +units=m"

This also looks odd:

newproj <- "+proj=lonlat +lat_1=52 +lon_0=-10 +ellps=WGS84"

How about

newproj <- "+proj=longlat +datum=WGS84"